摘要
利用多种海洋资料,采用经验正交函数分解(EOF)与合成分析等方法研究了热带太平洋-印度洋热含量年际变化的主要模态及其对应的转换过程。结果表明其第一模态对应El Nino事件成熟位相时的空间分布,即热带西太平洋和东印度洋为一冷中心,西南印度洋和赤道东太平洋为暖中心;第二模态对应着El Nino事件过渡期的空间分布,太平洋10°N附近以及赤道带为变化中心,而印度洋的变化中心主要在苏门答腊岛西部的赤道东印度洋海区。这2个模态基本刻画了ENSO循环过程中热带两大洋热含量变化的关键海区。利用合成分析结果与EOF分解结果的相似性,探讨了EOF分解前两个模态之间的转换过程,发现第一模态可能主要是通过海洋波动的传播过程调整到第二模态的,而第二模态还可以作为El Nino或La Nina事件的预报因子。此外,分析结果还表明,El Nino事件与La Nina事件对应的热含量变化并不是反对称的。
Based on various ocean data sets the main modes of heat content anomaly in the tropical Pacific-Indian Ocean are studied on interannual time scale, using various methods such as Empirical Orthogonal Function analyses （EOF） and composite analysis. The results turn out that for the first EOF mode its spatial distribution represents the mature phase of ENSO with the warm center located in the southwest Indian Ocean and eastern Pacific and the cold center located in the eastern Indian Ocean and western Pacific respectively. The second EOF mode （EOF2） is the transition mode of ENSO with its variation center located in the zonal belt of the equatorial region, around 10°N in the Pacific and near the equatorial eastern region of the Indian Ocean. These two modes together reflect the key area of heat content variation during ENSO cycle. Composite analysis is also carried out to explore the interactive conversion between the two EOF modes, considering the similarity of the EOF results with the composite results. It is found that the oceanic waves may be mainly responsible for the conversion between these two EOF modes. It is also demonstrated that the La Nina and El Nino events are not asymmetric with respect to each other.
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2007年第3期365-371,共7页
Periodical of Ocean University of China
基金
国家自然科学基金项目(40233033
40576006)资助
关键词
热带太平洋
热带印度洋
热含量
主模态
海洋波动
Tropical Pacific
Tropical Indian Ocean
heat content
main mode
oceanic waves
